1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a ball spacer formed between two substrates of a liquid crystal display (LCD) device to maintain a cell gap therebetween.
2. Discussion of the Related Art
Among the various types of ultra-thin flat type display devices, which include devices having display screens with a thickness of several centimeters, liquid crystal display (LCD) devices have advantages such as low power consumption and portability, and are widely used in applications such as notebook computers, monitors, and aircraft.
An LCD device includes lower and upper substrates facing each other at a predetermined interval therebetween, and a liquid crystal layer formed between the lower and upper substrates. Spacers are formed between the lower and upper substrates to maintain a cell gap therebetween.
In a related art process using sphere-shaped spacers, ball spacers are suspended in a solvent to produce a suspension solution having a predetermined density of ball spacers. The solution containing the ball spacers is sprayed onto the substrate through a nozzle.
When the solution is sprayed through the nozzle onto a substrate, the ball spacers may be sprayed onto pixel regions of the substrate where spacers are not desired, resulting in a deterioration of the picture quality of the LCD device. Accordingly, an ink-jet method has been proposed as an alternative to the solution spraying method.
FIG. 1 is a perspective view schematically illustrating a method for forming ball spacers through a related art ink-jet method.
As shown in FIG. 1, an ink-jet apparatus 30 is moved in the direction indicated by the arrow above a substrate 10 including a pixel area and a non-pixel area. While the ink-jet apparatus 30 is moving above the substrate 10, ball spacers are dispensed onto the non-pixel area of the substrate 10 by the ink-jet apparatus 30.
The ink-jet apparatus 30 comprises an ink head for storing a solution containing the ball spacers, and a nozzle for dispensing the solution containing the ball spacers onto the substrate 10.
As the ink-jet apparatus 30 moves above the substrate 10, the solution containing the ball spacers is dispensed onto the substrate 10 through the nozzle. The solution dispensed on the substrate 10 then dries. That is, the solvent evaporates from the solution, leaving the ball spacers on the substrate 10.
In the ink-jet apparatus 30 method described above, the ball spacers 50 are formed in the desired portion of the substrate by controlling the nozzle to control the dispensing of solution. Accordingly, the ball spacers 50 may be formed on the non-pixel area of the substrate 10 only, thereby preventing the deterioration of picture quality.
However, even though the ball spacers 50 are formed on the non-pixel area of the substrate 10, the ball spacers may be moved from the non-pixel area to the pixel area during a movement of the substrate 10 such as during a transfer.
In addition, when dispensing the ball spacer solution through the nozzle, the proximity of dispensed drops of the solution may allow the drops to merge producing a large drop. As the dispensed drops merge into a large drop, the ball spacers 52 may be moved onto the pixel area of the substrate 10.
As described above, even when the ball spacers are formed using the ink-jet apparatus, the ball spacers 52 may be moved to the pixel area when transferring the substrate or while dispensing the ball spacer solution, thereby deteriorating the picture quality.